One of Hong Kong's most powerful legal lobbying groups has thrown its weight behind the fight to retain by-elections to fill midterm vacancies in the Legislative Council, in the face of the government's bid to ban them.

Hong Kong Law Society president Junius Ho Kwan-yiu yesterday laid out for the first time the society's view on the issue, saying it was right and constitutional to keep by-elections to replace a legislator who resigns.

The government proposed scrapping by-elections in the wake of last year's resignations by five pan-democrat lawmakers who wanted to force what they said would be a de facto referendum on universal suffrage.

The government said the polls, which attracted a small turnout and saw the lawmakers who quit comfortably re-elected, had angered the public because of their cost.

It says changing the law would close the loophole that allowed the lawmakers to engineer the de facto referendum.

After an initial public outcry over the proposal and claims that it eroded civil liberties, the government launched a two-month consultation on ways to fill Legco vacancies arising between full elections.

Under three of the four options put forward, the option of a by-election would remain, but under two of them the vacancy was more likely to be filled automatically by a candidate who ran in the original election.

'If there is a consensus about what the government should do, it would be wrong for the government to go against it,' Ho said.

'What I am concerned about is the scrapping of by-elections, which had been effective in replacing legislators,' he told a radio programme.

Ho said one of the government proposals, under which a legislator who resigned would be barred from standing in by-elections for the remainder of the term of office, seemed like a rational way to resolve concerns arising from the de facto referendum.

It would not, he believed, violate a stipulation of the Basic Law which guarantees every citizen's right to stand for election, as it was a proportionate solution.

Under the second and the third options, a lawmaker who resigned or died would be replaced by the next-best-ranked candidate from their slate at the previous election.

While he stressed that the society would study the consultation document before responding to it, Ho said the automatic replacement mechanism would make a by-election a last resort, which was not desirable.

'I believe whenever there is a vacancy, the first thing to be done is to have a by-election,' he said.

Ho argued that cost should not be a consideration when assessing whether or not a by-election should be conducted.

'Money should not be a concern when we talk about keeping a democratic system running properly,' he said.

He also said that a fourth option, which would leave a Legco seat vacant if there was no remaining candidate on the departing lawmaker's list, was unreasonable.

'It is not desirable to leave a seat vacant. In the future, there will be 70 legislators. If a seat becomes vacant six months after an election, there will be more than three years when the seat is vacant. This is not preferred,' he said.